1. Field of the Invention
This invention pertains to internal combustion motorcycle engines. More specifically, this in invention pertains to a motorcycle engine case that comprises an adjustable oil scraper that allows the engine case to accommodate a range of flywheel dimensions.
2. General Background
Motorcycle engines often comprise one or more flywheels that are located within the engine case and that are rotational fixed to the crankshaft. Such a flywheel typically comprises a cylindrical or a partial cylindrical outer surface that is aligned with the crankshaft axis. The engine case typically comprises a stationary oil scraper that has a scraping edge that is positioned very close to the cylindrical outer surface of the flywheel. As the flywheel rotates within the engine case, the oil scraper engages oil that clings to the cylindrical outer surface of the flywheel and removes such oil from the flywheel. The oil removed from the flywheel by the scraper is then channeled to the oil pump.
In some situations, motorcycle owners desire replacing one flywheel with another smaller or larger flywheel. For example, by replacing standard OEM flywheels with slightly smaller flywheels, engine acceleration can be improved due to the corresponding reduction in the rotational moment of inertia of the flywheels. Of course, the reduction of the rotational moment of inertia results in less even torque between the power strokes of the engine, and is therefore not always desired. Additionally, the oil scraper of the OEM engine case is fixed in position and is therefore adapted and configured to function properly only in combination with a specific flywheel diameter. Thus, the oil scraper of the OEM engine case would not function properly with a flywheel that is smaller than the OEM flywheel and would prevent a larger flywheel from being utilized. For this reason, motorcycle owners that wish to use non-OEM sized flywheels typically must replace the OEM engine case with one that is specifically adapted for the alternatively sized flywheel.